The family is well known for the aromatic volatile or essential oils in the foliage, which are used in perfumes, flavorings, and medicines. Among the more important essential oils are those derived from sage, lavender, rosemary, patchouli, and the true mints. Many of the commonly used potherbs are from the mint family, e.g., basil, thyme, savory, marjoram, oregano, and the plants mentioned above. As is true of most potherbs and spices, these have a history of medicinal use in domestic remedies. Catnip, pennyroyal, hyssop, self-heal, the horehound of confectionery, and curative teas from such plants as bee balm and yerba buena have been similarly used. Species of the Labiatae are often grown as ornamentals as well as in herb gardens, and in the United States several have escaped cultivation and become naturalized as wildflowers. Types of hyssop, sage, pennyroyal, mint, and lavender are among the prevalent native species.
The true mints belong to the genus Mentha. Commercially the most important species is peppermint (M. piperita). The leaves and tops are sometimes dried and utilized for flavoring and in medicine but are chiefly in demand for the oil, distilled out for use as a carminative and stimulant, for its derivative menthol (obtained also from other mints), and for flavoring purposes, especially in chewing gum and candy and as a disguise for disagreeable tastes of drugs. Spearmint (M. spicata) is distinguishable from peppermint by the absence of a leafstalk. Its flavor is milder (the aromatic principle is carvone), and it too is used in chewing gum and medicines and is often cultivated in gardens as a flavoring. Both plants are European perennials now naturalized in the United States.
Also useful medicinally and as a source of an essential oil is the pennyroyal. True, or European, pennyroyal (M. pulegium) is a prostrate perennial. The species name [Lat.,=fleabane] is an herbalist's name given for the plant's supposed property of driving away fleas. The related American pennyroyal (Hedeoma pulegioides) is a branching annual; pennyroyal tea was a traditional domestic remedy. Other American species of Hedeoma and similar genera are also called pennyroyal. The mint family is classified in the division Magnoliophyta, class Magnoliopsida, order Lamiales.
Mint-made errors are errors in a coin made by the mint during the minting process. They are almost always accidental and in modern minting are usually very rare, making them valuable to numismatists. Minting errors are far more common in older coinage, understandably. Authentic error coins must not be confused with coins that have incurred damage after being minted.
Planchet errors occur when the wrong coin blanks, or planchets, are fed into a coin-stamping press. This results in a coin that has been stamped with a design intended for a differently sized coin; this is called a wrong planchet error. In addition, unminted or blank planchets are occasionally produced. The results are usually obvious errors that are also prized by collectors, though the errors are usually caught in manufacturing and destroyed. Blank planchets with rims are valued lower than those with no rim.
A Kennedy half dollar struck on a Susan B. Anthony planchet is extremely rare. Sacagawea dollars exist with a state quarter design on the back; this type of error is called a mule, and unintentional ones are rare.
Hub and die errors are the result of faults in the coin hub or coin die. There are many different kinds of such errors. Modern coins are still released with hub and die errors, because the defects are too small to be seen with the naked eye. A few exceptions exist, where the dies are used despite producing easily visible flaws. The 1955 Lincoln cent is an example.
Strike errors occur when the planchet is struck. It is a fault in the manufacturing process rather than in either the die or the planchet. A standard type of strike error is a broadstrike, where the rim image is not struck into the coin's edge because the collar die was missing. Numismatists often prize strike error coins over perfectly struck examples, which tend to be more common, but less highly than die error coins, which are usually rarer, making it valuable.